Heresy with H II motorboard

[colterphoto1]

So here's the plan. For some time now we've known about the parts upgrade kit that Klipsch has available for the HII-> H III, right? (there's a bunch of threads about this so I'm not going to review that here). Suffice to say that it's a very economical upgrade kit, especially after you factor in getting somthing back from your old parts.

But what about those of us with the original Heresy that we love, or cabinets that don't seem worthy of the upgrade? Well here's an answer for you- how about modifying a Heresy cabinet with new motor board and grille so that the H II (or better yet H III) components could be retrofitted. While this is not a beginner's project, it is possible and with the right tools and techniques it can look very good.

In April of this year, I visited Groomlakearea 51 (Marshall), to document his lastest woodworking techniques and experiments with the Heritage series.

In this series of photos, we are reconstructing an entire cabinet from scratch, as the original was damaged beyond repair. Still, for each Heritage cabinet that he builds, Marshall maintains an inventory of factory-numbered backs, indicating that new cabinets are not being manufactured.

In order to complete the build/photo series in a timely manner, the panels were precut on DeWalt tablesaw and all brace material was ripped. The technique for manufacturing motor boards and grille blanks is detailed previously and are referenced there. We started with a stack of panels, raw components, and assembly tools. Marshall has carefully investigated the tools actually used by the factory in Hope and the same joinery and methods of attachment are used whereever practicable.

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The Heresy II/ III motor board differs from the Heresy in several important ways. The drivers are loaded from the front, so they are rabbets allowing the front to be relatively flush. The drivers are also located differently than in the Heresy I, so although the cabinets are the IDENTICAL SIZES, the same grill board will not even function due to driver placement.

The solution for those with earlier model Heresies is to replace the motor board with a type identical to the Heresy II. In this way your favorite cabinet can be retrofitted with the latest in Klipsch authorized update kits, the Heresy III component package.

Here we are assembling the cabinet side walls using a nail gun. Unlike staples, nails don't cause the wood surface to pucker, nor leave a void. This means that they are good fasteners for this rough cabinet that will be veneered later. The cabinet is laid on it's side on a known flat surface, in this case the deck of DeWalt table saw. That should be nice and flat, yeah.

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Here's a little tool used to obtain the proper spacing for the front and glue nail blocks. Note that the are different. On the back you want the rear panel flush to the back of the sides. On the front you need the motor board inset slightly so that there is space for grille board on the front.

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Looking at that last photo, someone was thinking ahead when they had the black roller out. Not only was the back of the cabinet painted, but the front and edges of the motor board and grille board. Also the first couple of inches INSIDE the cabinet were painted as they will be seen later around the cracks next to the grille.

This photo reminds us to always lubricate air tools. The smallest drop that can be introduced into the tool is usually gets you through a sessions. Air tools are much better for assemble of this type because of their accuracy, neatness, and that they can create a very tight joint.

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The nail blocks will go in with a little glue (use a small bead, then wipe along the width of the board), stapled into place.

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We cut our nail blocks as we went, keeping everything tight inside the cabinet. One source of air leaks (causing loss of bass) is that Klispch cut their blocks slightly short and rarely put and sealant between the blocks.

With the H II cutout necessary to install the K79 tweeter from the front, we can see that there is only sufficient clearance for a tiny 1/2" thick piece of glue/nail block. Not very good for a speaker that's gonna have a 12" woofer pumping away in there. We need to devise a way to get enough glue block in there to secure the motor board. A real H II cabinet would have it's motor board dadoed into the cabinet walls, that adds quite a degree of stiffness. With a little deliberation we decide that the 1/2" supplemented with 3/4" block on either sides of the tweeter would be sufficient. Marshall may have devised another scheme for this after doing a couple of these cabinets, so I'll leave a couple of blank posts after this.

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glue block installation

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changes?

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inside of new cabinet, glue blocks installed.

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with a little planning, you might want to paint the rear sides of the back glue blocks, as some of that wood could be seen through the crack between the back and the cabinet sides after assembly.

Photo is a view of the motor board assembled using glue blocks. Motorboard is glued to blocks and stapled from the front.(? or back so you get a better looking motor board with grille off)

[colterphoto1]

Cabinet after components assembled from the front. Network installed to the inside side of cabinet, like in older H I's. If you are using the H III kit, you'll get a new large rectangular jack cut with crossover and wiring bundle attached. For that you'd drill a larger hole in the cabinet back, using a drill and jig saw (or router).

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Here's the H III kit from Klipsch. You get network/jack cup, horn, driver, tweeter, woofer, screws. (I'm not sure whether they still send a replacment horn or if you need to use your original K701- in which case if you're upgrading a H to H III, you'll need to order two of the horns also).

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close up view of rear of cabinet. In this case, customer had custom crossovers built to be installed like H networks so we followed a matching theme for inputs and installed these beauties from Parts Express.

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If you'd used Klispch's H III upgrade kit, you'd get the integrated jackcup/crossover network that looks like this. It can be installed anywhere on the lower portion of back of the cabinet so long as it does not interfere with the midrange driver. For some H II owners the hole will be pre-drilled, othes may have a round input jack cup. Those building from scratch or modifying H cabinets will need to trace a new hole, cutting 1/4" inside the tracing of the jack cup.

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components and motor board of real H III from Klipsch, yeah looks the same.

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here's our components, mounted in our H/HII/HIII motorboard

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The one on the Khorn Klipsch built. The one on the Belle, we built. A rebuilt Heresy, with Heresy II motorboard, custom network, and H III components.

How's it sound? Sounds GREAT! Easily blow away any standard K22 or K24 Heresy out there.

[Daddy Dee]

Michael,

Thanks for posting. Most interesting project here.

Marshall does darn good work. Not many diyers can pull off OEM quality like he does.

[CECAA850]

That's GOT to be Marshalls place. He's got the market cornered on Indian Blankets. Love the diffusers on the walls too. He does do beautiful work.

[Groomlakearea51]

Been busy.... In any event, Michael and I tested them extensively, and then back out to the workshop for driver removal for veneer and the grills. I used some special "reserved" birch with a "curly" wave like patterns, and golden oak stain. They look very similar to the H-III lacewood. Then coated with three thick coats of Minwax poly. The reason for use of poly as opposed to lacquer or oil is that they are for my daughter in her college apartment. Colter and I delivered them, installed and tested them and read the riot act to her roomates about putting anything on them, or cranking the amp past volume 11.... I also gave her a new Onkyo 8555 amplifier (which is what my son has in his room with his K'horns), and new custom assembled speaker wire cable sets. I know what the amp will do, how it sounds, etc.

Colter has photos of the veneered "final product" which he'll post later today or tomorrow

I also did a different rear panel with a terminal cup as opposed to the binding post rear panel we used in the testing.